Can some help. I’m lost

space exploration has led to the development and technological improvement of many everyday items. (if this answer is wrong i will find the right answer) : )

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8

i believe the answer is d